“South Korea’s erratic behavior would only herald its final destruction.” That’s how North Korea diplomat Jon Yong Ryong responded to intense criticism of his country’s test of a nuclear weapon Feb. 12.

He was speaking at a United Nations conference on disarmament, and Britain’s representative Joanne Adamson said his statement was “completely inappropriate.”

North Korea conducted earlier nuclear tests in October 2006 and April 2009, linked on each occasion to a long-range missile test. It successfully launched a missile in December. Last April, Pyongyang was embarrassed when a missile disintegrated in flight.

Those most directly affected by this rocket rattling — in particular Japan, South Korea and the United States — are leading universal global protests against this belligerent behavior. The U.N. continues to censure and tighten sanctions. Most important, China has now joined the condemnation.

Pyongyang’s provocations reinforce international isolation and stymie prospects for diplomatic engagement, though the tests are used as leverage to try to pressure Washington into direct bilateral talks. Successive U.S. administrations have generally relied instead on the established Six Power framework for discussion, which means South Korea, China, Japan and Russia are also included.

The Bush administration, after initially flirting with unilateralism, gave renewed emphasis to the multilateral approach in dealing with North Korea. This example provides particularly persuasive evidence of the value of collective diplomacy, if any breakthrough is to be reached with this bizarre communist country.

The stakes are high. The Korean War of 1950 to 1953 took an estimated 1 million lives, and perhaps far more, brought direct combat between American and Chinese forces and devastated the Korean Peninsula. In the United States, a military stalemate destroyed public support for the Truman administration and anti-communist hysteria came to dominate domestic politics.

Currently, economic tools should be used aggressively against the North. Given its population’s exceptional poverty and suffering, financial pressure may bring positive results. Here, there is instructive recent precedent.

In 2007, Washington declared Macau-based Banco Delta Asia (BDA) to be a renegade financier underwriting illegal activities by Pyongyang, including global black market trade. U.S. companies were banned from doing business with BDA and others followed suit. Macau government authorities froze $25 million in North Korea funds on deposit.

Washington then offered to return the funds to Pyongyang in exchange for restraint in nuclear development activities. After the Korean communists caved in, at least temporarily, BDA carried out a transfer of funds. Practical pressure resulted in a more flexible North Korea, at least for a time.

Emphasis on economic carrots as well as sticks, combined with renewed but cautious diplomatic efforts, might pay off. Pyongyang remains notorious for extensive black market activities. China’s role is most pivotal. Its vital economic help is linked to worry about the sudden collapse of North Korea.

In the past, Pyongyang was skillful at creating crisis only to step back, usually in return for substantial economic assistance. Now, the regime inexorably escalates tensions. The power of the military, especially with inexperienced, new young leader Kim Jong Un in office, is probably a principal factor.

Yet, war has been averted since 1953. Patience linked to pragmatism may still pay off.